Before you start using compiz in linux mint 11 you most reinstall it before you use or you may find your self in a stand still and login in as root and delete the user and make a new one so to fix that i used some sudo:

Sudo apt-get purge compiz-extrasudo apt-get purge compizconfig-setting-mangerThen i reinstalled it by using synaptic Package Managersearch compizconfig-setting-manger and then search compiz-extra and then your good to go